Re-Thinking the Principle of Proportionality Outside of Hot Battlefields

42 Pages Posted: 20 Aug 2018

Date Written: September 27, 2015


The United States’ targeted strikes against members of Al-Qaeda, the Taliban, and associated forces outside of hot battlefields have generated significant debate on both legal and policy grounds. This Article argues that while enemy combatants can be targeted outside of hot battlefields under international humanitarian law (IHL), the traditional rule regarding collateral damage must be re-examined in these circumstances. This Article brings to light the serious concerns with applying the principle of proportionality – which permits attacks so long as the expected collateral damage is not excessive in relation to the military advantage anticipated – outside of hot battlefields by examining this principle’s unique historical development, its potential ethical justifications, and the key differences in the legal framework applicable in international armed conflicts (IACs) and non-international armed conflicts (NIACs). As a historical matter, this Article explains that the principle of proportionality developed in the context of IACs, where civilians were considered enemies due to their various roles in furthering the war fighting effort of their nation. The laws of war permitted significant civilian casualties in these contexts because civilians were deemed partially responsible for the armed conflict and thus liable to share in the hardships of war. In many circumstances, however, civilians residing outside of hot battlefields cannot be considered enemy civilians, as they may play no role in the underlying conflict. As such, we should question on legal and moral grounds whether these civilians should be subject to the same risks as civilians in IACs who to some degree further, and potentially benefit from, the conflict. Moreover, the balance struck by the principle of proportionality between military necessity and humanitarian objectives assumes that state parties in an IAC will take additional precautionary measures, consistent with their treaty obligations in IACs, to protect civilians. This assumption may not be warranted in NIACs as non-state actors often seek sanctuary outside of hot battlefields and intentionally conceal themselves among the civilian population. Finally, the infliction of collateral damage, even to the extent legally permitted by the principle of proportionality, may undermine key counter-insurgency and jus post bellum objectives. This Article concludes with some recommendations on how to modify the principle of proportionality when using force outside of hot battlefields.

Keywords: international humanitarian law, law of war, proportionality

Suggested Citation

Trumbull, Charles P, Re-Thinking the Principle of Proportionality Outside of Hot Battlefields (September 27, 2015). Virginia Journal of International Law, Vol. 55, 2015, Available at SSRN:

Charles P Trumbull (Contact Author)

U.S. Department of State ( email )

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